Java 创建时android中的文本观察程序_Java_Android_Textwatcher

Java 创建时android中的文本观察程序

java android

Java 创建时android中的文本观察程序,java,android,textwatcher,Java,Android,Textwatcher,我一直在尝试使用textwatcher。我从onCreate调用了函数addTextChangedListener（this），但应用程序因为这个命令而崩溃。请帮忙 private EditText txt1; private EditText txt2; private EditText txt3; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstan

我一直在尝试使用textwatcher。我从onCreate调用了函数addTextChangedListener（this），但应用程序因为这个命令而崩溃。请帮忙

private EditText txt1; 
private EditText txt2;
private EditText txt3;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);



     txt1 = (EditText) findViewById(R.id.signup_username);
     txt2 = (EditText) findViewById(R.id.signup_password);
     txt3 = (EditText) findViewById(R.id.signup_email);
    txt1.addTextChangedListener(this);
    txt2.addTextChangedListener(this);
    txt3.addTextChangedListener(this);
    if (savedInstanceState == null) {
        getFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }

}

以及：

@Override
    public void beforeTextChanged(CharSequence s, int start, int count,
            int after) {
}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
    // TODO Auto-generated method stub
}

@Override
public void afterTextChanged(Editable s) {
    View view = getCurrentFocus();
    int id = view.getId();
    if (id == R.id.signup_username) {
        String username = ((EditText) view).getText().toString();
        for (int i = 0; i < username.length(); i++) {
            if (username.charAt(i) < 'a' || username.charAt(i) > 'z') {
                Toast.makeText(getApplicationContext(), "Error", Toast.LENGTH_SHORT).show();
                break;
            }
            else {
                Toast.makeText(getApplicationContext(), "Murad", Toast.LENGTH_SHORT).show();
                break;
            }
        }
    }
    else {
        Toast.makeText(getApplicationContext(), "Oren", Toast.LENGTH_SHORT).show();
    }
}

}

@覆盖
更改前的公共无效（字符序列、整数开始、整数计数、，
整数后）{
}
@凌驾
public void onTextChanged（字符序列、int start、int before、int count）{
//TODO自动生成的方法存根
}
@凌驾
公共无效后文本已更改（可编辑）{
视图=getCurrentFocus（）；
int id=view.getId（）；
if（id==R.id.signup\u用户名）{
字符串用户名=（（编辑文本）视图）.getText（）.toString（）；
对于（int i=0；i'z'）{
Toast.makeText（getApplicationContext（），“Error”，Toast.LENGTH_SHORT.show（）；
打破
}
否则{
Toast.makeText（getApplicationContext（），“Murad”，Toast.LENGTH_SHORT）.show（）；
打破
}
}
}
否则{
Toast.makeText（getApplicationContext（），“Oren”，Toast.LENGTH_SHORT）.show（）；
}
}
}

日志：

04-03 11:37:22.684:D/skia（23439）：新的本地语言环境
04-03 11:37:22.854:D/libEGL（23439）：已加载/供应商/lib/egl/libEGL_-adreno.so
04-03 11:37:22.854:D/libEGL（23439）：已加载/供应商/lib/egl/libGLESv1_CM_adreno.so
04-03 11:37:22.864:D/libEGL（23439）：已加载/供应商/lib/egl/libGLESv2_-adreno.so
04-03 11:37:22.864:I/Adreno EGL（23439）：:EGL 1.4高通公司构建：（CL4169980）
04-03 11:37:22.864:I/Adreno EGL（23439）：OpenGL ES着色器编译器版本：17.01.10.SPL
04-03 11:37:22.864:I/Adreno EGL（23439）：建造日期：2013年9月26日星期四
04-03 11:37:22.864:I/Adreno EGL（23439）：本地分支机构：
04-03 11:37:22.864:I/Adreno EGL（23439）：远程分支：
04-03 11:37:22.864:I/Adreno EGL（23439）：局部贴片：
I/Adreno EGL（23439）：重建分支：
04-03 11:37:22.914:D/OpenGLRenderer（23439）：启用调试模式0
04-03 11:37:39.971:D/AndroidRuntime（23439）：关闭虚拟机
04-03 11:37:39.971:W/dalvikvm（23439）：threadid=1:线程以未捕获异常退出（组=0x41b2b898）
04-03 11:37:39.981:E/AndroidRuntime（23439）：致命异常：main
04-03 11:37:39.981:E/AndroidRuntime（23439）：java.lang.RuntimeException:无法启动活动组件信息{com.example.poca2/com.example.poca2.RegisterActivity}:java.lang.NullPointerException
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2295）
04-03 11:37:39.981:E/AndroidRuntime（23439）：位于android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2349）
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.app.ActivityThread.access$700（ActivityThread.java:159）
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1316）
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.os.Handler.dispatchMessage（Handler.java:99）上
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.os.Looper.loop（Looper.java:137）
04-03 11:37:39.981:E/AndroidRuntime（23439）：位于android.app.ActivityThread.main（ActivityThread.java:5419）
04-03 11:37:39.981:E/AndroidRuntime（23439）：位于java.lang.reflect.Method.Invokenactive（本机方法）
04-03 11:37:39.981:E/AndroidRuntime（23439）：位于java.lang.reflect.Method.invoke（Method.java:525）
04-03 11:37:39.981:E/AndroidRuntime（23439）：在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:1187）
04-03 11:37:39.981:E/AndroidRuntime（23439）：位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1003）
04-03 11:37:39.981:E/AndroidRuntime（23439）：在dalvik.system.NativeStart.main（本机方法）
04-03 11:37:39.981:E/AndroidRuntime（23439）：由以下原因引起：java.lang.NullPointerException
04-03 11:37:39.981:E/AndroidRuntime（23439）：位于com.example.poca2.RegisterActivity.onCreate（RegisterActivity.java:33）
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.app.Activity.performCreate（Activity.java:5372）上
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1104）
04-03 11:37:39.981:E/AndroidRuntime（23439）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2257）
04-03 11:37:39.981:E/AndroidRuntime（23439）：。。。还有11个
04-03 11:37:44.545:D/skia（23761）：新的本地语言环境
04-03 11:37:44.776:D/libEGL（23761）：已加载/vendor/lib/egl/libEGL_adreno.so
04-03 11:37:44.786:D/libEGL（23761）：已加载/vendor/lib/egl/libGLESv1_CM_adreno.so
04-03 11:37:44.786:D/libEGL（23761）：已加载/vendor/lib/egl/libGLESv2_adreno.so
04-03 11:37:44.786:I/Adreno EGL（23761）：:EGL 1.4高通公司构建：（CL4169980）
04-03 11:37:44.786:I/Adreno EGL（23761）：OpenGL ES着色器编译器版本：17.01.10.SPL
04-03 11:37:44.786:I/Adreno EGL（23761）：建造日期：2013年9月26日星期四
04-03 11:37:44.786:I/Adreno EGL（23761）：本地分行：
04-03 11:37:44.786:I/Adreno EGL（23761）：远程分支：
04-03 11:37:44.786:I/Adreno EGL（23761）：局部贴片：
04-03 11:37:44.786:I/Adreno EGL（23761）：重建分支：
04-03 11:37:44.836:D/OpenGLRenderer（23761）：启用调试模式0
04-03 11:37:48.069:D/AndroidRuntime（23761）：关闭虚拟机
04-03 11:37:48.069:W/dalvikvm（23761）：threadid=1:线程退出时出现未捕获异常（组=0x41b2b898）
04-03 11:37:48.069:E/AndroidRuntime（23761）：致命异常：主
04-03 11:37:48.069:E/AndroidRuntime（23761）：java.lang.RuntimeException:无法启动活动组件信息{com.example.poca2/com.example.poca2.RegisterActivity}:java.lang.NullPointerException
04-03 11:37:48.069:E/AndroidRuntime（23761）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2295）
04-03 11:37:48.069:E/AndroidRuntime（23761）：位于android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2349）
04-03 11:37
04-03 11:37:22.684: D/skia(23439): new locale en-Latn-GB
04-03 11:37:22.854: D/libEGL(23439): loaded /vendor/lib/egl/libEGL_adreno.so
04-03 11:37:22.854: D/libEGL(23439): loaded /vendor/lib/egl/libGLESv1_CM_adreno.so
04-03 11:37:22.864: D/libEGL(23439): loaded /vendor/lib/egl/libGLESv2_adreno.so
04-03 11:37:22.864: I/Adreno-EGL(23439): <qeglDrvAPI_eglInitialize:316>: EGL 1.4 QUALCOMM build:  (CL4169980)
04-03 11:37:22.864: I/Adreno-EGL(23439): OpenGL ES Shader Compiler Version: 17.01.10.SPL
04-03 11:37:22.864: I/Adreno-EGL(23439): Build Date: 09/26/13 Thu
04-03 11:37:22.864: I/Adreno-EGL(23439): Local Branch: 
04-03 11:37:22.864: I/Adreno-EGL(23439): Remote Branch: 
04-03 11:37:22.864: I/Adreno-EGL(23439): Local Patches: 
04-03 11:37:22.864: I/Adreno-EGL(23439): Reconstruct Branch: 
04-03 11:37:22.914: D/OpenGLRenderer(23439): Enabling debug mode 0
04-03 11:37:39.971: D/AndroidRuntime(23439): Shutting down VM
04-03 11:37:39.971: W/dalvikvm(23439): threadid=1: thread exiting with uncaught exception (group=0x41b2b898)
04-03 11:37:39.981: E/AndroidRuntime(23439): FATAL EXCEPTION: main
04-03 11:37:39.981: E/AndroidRuntime(23439): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.poca2/com.example.poca2.RegisterActivity}: java.lang.NullPointerException
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.ActivityThread.access$700(ActivityThread.java:159)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.os.Handler.dispatchMessage(Handler.java:99)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.os.Looper.loop(Looper.java:137)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.ActivityThread.main(ActivityThread.java:5419)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at java.lang.reflect.Method.invokeNative(Native Method)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at java.lang.reflect.Method.invoke(Method.java:525)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at dalvik.system.NativeStart.main(Native Method)
04-03 11:37:39.981: E/AndroidRuntime(23439): Caused by: java.lang.NullPointerException
04-03 11:37:39.981: E/AndroidRuntime(23439):    at com.example.poca2.RegisterActivity.onCreate(RegisterActivity.java:33)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.Activity.performCreate(Activity.java:5372)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
04-03 11:37:39.981: E/AndroidRuntime(23439):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257)
04-03 11:37:39.981: E/AndroidRuntime(23439):    ... 11 more
04-03 11:37:44.545: D/skia(23761): new locale en-Latn-GB
04-03 11:37:44.776: D/libEGL(23761): loaded /vendor/lib/egl/libEGL_adreno.so
04-03 11:37:44.786: D/libEGL(23761): loaded /vendor/lib/egl/libGLESv1_CM_adreno.so
04-03 11:37:44.786: D/libEGL(23761): loaded /vendor/lib/egl/libGLESv2_adreno.so
04-03 11:37:44.786: I/Adreno-EGL(23761): <qeglDrvAPI_eglInitialize:316>: EGL 1.4 QUALCOMM build:  (CL4169980)
04-03 11:37:44.786: I/Adreno-EGL(23761): OpenGL ES Shader Compiler Version: 17.01.10.SPL
04-03 11:37:44.786: I/Adreno-EGL(23761): Build Date: 09/26/13 Thu
04-03 11:37:44.786: I/Adreno-EGL(23761): Local Branch: 
04-03 11:37:44.786: I/Adreno-EGL(23761): Remote Branch: 
04-03 11:37:44.786: I/Adreno-EGL(23761): Local Patches: 
04-03 11:37:44.786: I/Adreno-EGL(23761): Reconstruct Branch: 
04-03 11:37:44.836: D/OpenGLRenderer(23761): Enabling debug mode 0
04-03 11:37:48.069: D/AndroidRuntime(23761): Shutting down VM
04-03 11:37:48.069: W/dalvikvm(23761): threadid=1: thread exiting with uncaught exception (group=0x41b2b898)
04-03 11:37:48.069: E/AndroidRuntime(23761): FATAL EXCEPTION: main
04-03 11:37:48.069: E/AndroidRuntime(23761): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.poca2/com.example.poca2.RegisterActivity}: java.lang.NullPointerException
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.ActivityThread.access$700(ActivityThread.java:159)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.os.Handler.dispatchMessage(Handler.java:99)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.os.Looper.loop(Looper.java:137)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.ActivityThread.main(ActivityThread.java:5419)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at java.lang.reflect.Method.invokeNative(Native Method)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at java.lang.reflect.Method.invoke(Method.java:525)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at dalvik.system.NativeStart.main(Native Method)
04-03 11:37:48.069: E/AndroidRuntime(23761): Caused by: java.lang.NullPointerException
04-03 11:37:48.069: E/AndroidRuntime(23761):    at com.example.poca2.RegisterActivity.onCreate(RegisterActivity.java:33)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.Activity.performCreate(Activity.java:5372)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
04-03 11:37:48.069: E/AndroidRuntime(23761):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257)
04-03 11:37:48.069: E/AndroidRuntime(23761):    ... 11 more
04-03 11:37:54.265: I/Process(23761): Sending signal. PID: 23761 SIG: 9

private EditText txt1; 
private EditText txt2;
private EditText txt3;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);



    txt1 = (EditText) findViewById(R.id.signup_username);
    txt2 = (EditText) findViewById(R.id.signup_password);
    txt3 = (EditText) findViewById(R.id.signup_email);
    txt1.addTextChangedListener(new CustomTextWatcher(txt1, getApplicationContext()));
    txt2.addTextChangedListener(new CustomTextWatcher(txt2, getApplicationContext()));
    txt3.addTextChangedListener(new CustomTextWatcher(txt3, getApplicationContext()));
    if (savedInstanceState == null) {
        getFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }

}
 class CustomTextWatcher implements TextWatcher {
EditText m;
Context c;
public CustomTextWatcher (EditText e, Context context) {
    m = e;
    c = context;
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count,
        int after) {
    // TODO Auto-generated method stub

}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
    // TODO Auto-generated method stub

}

@Override
public void afterTextChanged(Editable s) {
    int id = m.getId();
    if (id == R.id.signup_username) {
        String username = ((EditText) m).getText().toString();
        for (int i = 0; i < username.length(); i++) {
            if (username.charAt(i) < 'a' || username.charAt(i) > 'z') {
                Toast.makeText(c, "Error", Toast.LENGTH_SHORT).show();
                break;
            }
            else {
                Toast.makeText(c, "Murad", Toast.LENGTH_SHORT).show();
                break;
            }
        }
    }
    else {
        Toast.makeText(c, "Oren", Toast.LENGTH_SHORT).show();
    }
}